Update group statistics when some columns on ProjectStatistics are updated

What does this MR do?

Schedules a Namespace::AggregationSchedule worker if some of the project statistics are refreshed.

The worker is only executed if the feature flag is enabled.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers

Related to #62214 (closed)